A set of frames for two to four 24mm arcade buttons. I've got them wired to my raspberry pi's GPIO pins - there's an "enclosure plugin" for octoprint that'll let you assign printer actions or shell scripts, to GPIO inputs.
The buttons are just momentary switches and they're pretty cheap and reasonably good looking.

I've only printed the L one, but the others are made with the same dimensions. It's mounted to the leg of my Lack table with command strips.